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| author | Miklos Szeredi | 2006-10-17 09:10:06 +0200 |
|---|---|---|
| committer | Linus Torvalds | 2006-10-17 17:18:45 +0200 |
| commit | 9ffbb9162312fd8113037cb3d94f787f06bbfa9a (patch) | |
| tree | a8194bb542dcda56271b44d7de23f2a72ecac900 /fs/fuse/file.c | |
| parent | [PATCH] sx: fix user-visible typo (devic) (diff) | |
| download | kernel-qcow2-linux-9ffbb9162312fd8113037cb3d94f787f06bbfa9a.tar.gz kernel-qcow2-linux-9ffbb9162312fd8113037cb3d94f787f06bbfa9a.tar.xz kernel-qcow2-linux-9ffbb9162312fd8113037cb3d94f787f06bbfa9a.zip | |
[PATCH] fuse: fix hang on SMP
Fuse didn't always call i_size_write() with i_mutex held which caused rare
hangs on SMP/32bit. This bug has been present since fuse-2.2, well before
being merged into mainline.
The simplest solution is to protect i_size_write() with the per-connection
spinlock. Using i_mutex for this purpose would require some restructuring of
the code and I'm not even sure it's always safe to acquire i_mutex in all
places i_size needs to be set.
Since most of vmtruncate is already duplicated for other reasons, duplicate
the remaining part as well, making all i_size_write() calls internal to fuse.
Using i_size_write() was unnecessary in fuse_init_inode(), since this function
is only called on a newly created locked inode.
Reported by a few people over the years, but special thanks to Dana Henriksen
who was persistent enough in helping me debug it.
Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'fs/fuse/file.c')
| -rw-r--r-- | fs/fuse/file.c | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/fs/fuse/file.c b/fs/fuse/file.c index 183626868eea..2bb5ace3882d 100644 --- a/fs/fuse/file.c +++ b/fs/fuse/file.c @@ -481,8 +481,10 @@ static int fuse_commit_write(struct file *file, struct page *page, err = -EIO; if (!err) { pos += count; - if (pos > i_size_read(inode)) + spin_lock(&fc->lock); + if (pos > inode->i_size) i_size_write(inode, pos); + spin_unlock(&fc->lock); if (offset == 0 && to == PAGE_CACHE_SIZE) { clear_page_dirty(page); @@ -586,8 +588,12 @@ static ssize_t fuse_direct_io(struct file *file, const char __user *buf, } fuse_put_request(fc, req); if (res > 0) { - if (write && pos > i_size_read(inode)) - i_size_write(inode, pos); + if (write) { + spin_lock(&fc->lock); + if (pos > inode->i_size) + i_size_write(inode, pos); + spin_unlock(&fc->lock); + } *ppos = pos; } fuse_invalidate_attr(inode); |